Department of Mathematics, University of Oulu, Oulu, Finland ; Université Catholique de Louvain, Institut Mathématique, B-1348 Louvain-la-Neuve, Belgium
Abstract:
The aim of this paper is to consider the radially-symmetric periodic-Dirichlet problem on for the equation
where is the classical Laplacian operator, and denotes the open ball of center and radius in When is a sufficiently large irrational with bounded partial quotients, we combine some number theory techniques with the asymptotic properties of the Bessel functions to show that is not an accumulation point of the spectrum of the linear part. This result is used to obtain existence conditions for the nonlinear problem.